Compasses. The good, the bad and the ugly.

Rabbitguts

Malcolm Douglas
Joined
May 16, 2013
Messages
31
Reaction score
0
i had a silva compass develop a bubble in it with in a year of me owning it, took it back to the store under warranty. the shop who were the main australian importers at the time said that there was a problem with the ones made in a specific country (can not remember which but an asian country) got a new replacement and 15 years later this has no bubble. this one is made in europe.
 

Mickldo

Ray Mears
Joined
Oct 28, 2012
Messages
424
Reaction score
1
Location
Maryborough, Qld
Hi mate. A small bubble wont affect the accuracy of the compass. It may become an issue with larger bubbles where the needle could, perhaps, possibly become deflected slightly by the surface tension of the bubble but I wouldn't consider it a catastrophic problem unless the bubble becomes very large. Some manufacturers I beleve will replace a compass that has a bubble but ive never had to do this as its never been a problem for me as I dont have a dampened compass. I use a Silva Ranger base plate compass and a Cammenga lensatic compass, depending on what Im doing. As you say the liquid is really only there to dampen erratic needle movement so I cant see it being an issue unless your doing some high speed orienteering competition. A bubble can appear depending on altitude and temperature and can become larger as the water contracts. If you are worried you could leave it in the sun for a bit to warm before taking a bearing.

A compass is only accurate to a certain level when used with a map and on foot travel in my humble opinion. Ive never needed to hit a mark so specific that a bubble would worry me as I usually shoot for some kind of terrain feature that I can identify by eye and go from there. Then again, I play 99% of the time in country with terrain so it might be a bigger concern for our flat country members. I think you called it right Mick.

As for how to avoid it. Im not really sure how they form, if its a temp /altitude issue or a manufacturing issue. I imagine that if the bubble is going away and coming back then its just an environmental influence. If the bubble is growing overtime I would suspect there is a leak and most quality makers would likely replace it within warranty. The only other thing I can think of is purchasing an oil filled compass, perhaps these are more stable and less likely to develop bubbles? I would need someone to comment on this as Ive never owned one either.

In summing up.. A small bubble I wouldn't worry about, a large growing bubble might be another matter.
Yeah, I don't reckon it is too big a problem either. I was just asking as the organisers of the event had rejected the compass the patrol had and I had to lend them my personal compass. If they are going to hold an event at night, in the middle of winter and then penalize entrants for an environmental problem that isn't that big a deal then that is a bit rich. I didn't question it with them at the time as I didn't have the facts but I will bring it up if we get penalized again.
 

Thrud

Richard Proenneke
Joined
Mar 9, 2013
Messages
2,028
Reaction score
245
Location
Perth, WA
There was a problem with the versions that were made in the USA by Brunton, check that your Silva or Suunto come from the correct Scandinavian country!
 

ninefivefox

Mors Kochanski
Joined
Mar 28, 2013
Messages
357
Reaction score
3
In 1994 I purchased a silva prismatic in mils, I have punished that compass from pooring rain to being left in my shirt pocket and going through the washing machine and dryer. The roma has mostly faded and she needs a good blast of touch to glow at night; however, every time I've checked the calibration she has been spot on. I realise that degrees minutes seconds is more accurate but I mils works for me.

http://silva.se/products/proffessional/expedition-54b

When I purchased mine it was about $60 for the plain and $100 for the prismatic , now the retail for $220.
 

GTVi

John McDouall Stuart
Joined
Dec 13, 2011
Messages
581
Reaction score
0
Location
Adelaide
Just thought I'd give some input. My Silvia Ranger 27 developed a small bubble, about 3-4mm diameter.
I was about to throw it out because it was interfering with a good reading.
I placed it in hot water about 50 degrees C, and left it for a few minutes.
The bubble has now completely vanished.
Just thought I'd put it out there for anyone else that has the same problem.
 

thejungleisneutral

Walkabout
Joined
Mar 18, 2014
Messages
479
Reaction score
56
Location
Southern Tablelands, NSW
That's good to know GTVi. Thanks.

I haven't had bubble issues with a baseplate compass, but I had them with one of my WWII prismatic compasses and found that being left out in direct sunlight for a day dissipated the bubble and re-pressurised the capsule - well, that's how it looks to me anyway. I have since removed huge bubbles from these old compasses during the refurbishing process using a hydraulic solution to the problem.

So with the baseplate compasses, the hot water treatment appears to do the same thing as leaving the prismatic capsule out in summer sun - it causes the liquid to expand, the bubbles are caught in the in-built bubble-traps and the problem goes away, at least temporarily. It's a good solution and one you could do in the field in a canteen cup or billy if you had to fix the compass then and there.
 
Top